CS488 - Introduction to Computer Graphics - Lecture 22

Comments and Questions

  1. Exam: April 16th, 2008, 09.00, RCH???



Almost all the effects are effects of energy

Light is both a particle and a wave


Light travels in straight lines

Light travels fast


The easiest way to think about light.

Particles have a property


`Wavelength' suggests waves.

Actually two competing theories

Two hundred years ago the wave theory won.

One hundred years ago a compromise solution was found


Colour is the first application of linear algebra.

Grassmann: We don't know what colour is but we know it has certain properties. Let's build a formal system with the properties and see what comes out.

  1. Focus on matching
  2. Focus on additive mixture
  3. Observe linearity
  4. How many primaries?
  5. You need subtraction

So we now have a formal model of colour

  1. Choose three standard primaries
  2. Express a colour in terms of the primaries
  3. You can reproduce it exactly

Expressing a colour in terms of the primaries

  1. The colour matching experiment

In practice, the `colour gamut' is an issue

Models of Colour in Computer Graphics

Have an output device with three primaries

  1. Express the colour in terms of those primaries
  2. You need to do a change of basis, which you know well how to do.
  3. But first you need to calibrate the device, which you may not know how to do.

Natural Phenomena

The General Idea

Human Skin

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